The present invention relates to a method and apparatus for assembling a rolling bearing, and more particularly to a method and apparatus for assembling a double row tapered roller bearing.
A wheel of a motor vehicle is supported rotatably relative to a suspension system on a body side by a rolling bearing, and a wheel of a heavy vehicle such as a bus or a truck in motor vehicles is normally supported by a double row tapered bearing in which tapered rollers are arranged in double rows.
Incidentally, rolling bearings having a construction referred to as a so-called third generation hub unit have been proposed with a view to reducing the number of constituent components to thereby reduce production costs. As is shown in FIG. 10, this hub unit includes a hub main body 51, an inner ring 52 fixedly fitted on one end portion of the hub main body 51, an outer ring 53 provided on an outside diameter side of the inner ring 52 and the hub main body 51, a first row of tapered rollers 54a and a second row of tapered rollers 54b which are provided rollingly between an outer circumferential surface of the inner ring 52 and the hub main body 51 and an inner circumferential surface of the outer ring 53 and a first seal ring 55a and a second seal ring 55b which are adapted to form a seal between inner circumferential surfaces of both end portions of the outer ring 53 and the outer circumferential surface of the hub main body 51 and an outer circumferential surface of an end portion of the inner ring 52 which confronts an inner side of the vehicle (a right-hand side as viewed in FIG. 10). In addition, a flange 56 for mounting a wheel (not shown) is provided at an end portion of the hub main body 51 which confronts an outer side of the vehicle, and on an outer circumferential surface of an intermediate portion of the hub main body, a first inner ring raceway 58a is formed in such a manner as to confront, of the two raceways, that is, the first outer ring raceway 57a and the second outer ring raceway 57b, the first outer ring raceway 57a which is disposed on the outer side of the vehicle (a left-hand side as viewed in FIG. 10). In addition, a second inner ring raceway 58b is formed in such a manner as to confront the second outer ring raceway 57b on an outer circumferential surface of the inner ring 52 fitted on to be fixed to an end portion of the hub main body 51 which confronts the outer side of the vehicle.
The vehicle outer side tapered rollers 54 are arranged circumferentially at equal intervals between the first outer ring raceway 57a and the first inner ring raceway 58a by a cage 60a, and the vehicle inner side tapered rollers 54b arranged circumferentially at equal intervals between the second outer ring raceway 57b and the second inner ring raceway 58b by a cage 60b. In addition, in FIG. 10, reference numeral 59 denotes a splined hole formed in a central portion of the hub main body 51 with which an end portion of a drive shaft or axle (not shown) of the vehicle is brought into spline engagement.
In the hub unit constructed as has been described above, since the flange portion 56 is formed at the vehicle outer side end portion of the hub main body 51, the vehicle outer side seal ring 55a needs to be provided on an inner circumferential surface of the vehicle outer side end portion of the outer ring 53 before the hub main body 51 is inserted into the outer ring 53. Consequently, being different from a conventional double row tapered roller bearing, this hub unit is assembled by a method described, for example, in JP-A-2004-257553.
Namely, as is shown in FIG. 11, firstly, a subassembly member 70 is prepared in which the vehicle outer side cage 60a and the tapered rollers 54a are combined with each other, and this subassembly member 70 is then combined with the outer ring 53. More specifically, the subassembly member 70 is set on the first outer ring raceway 57a. 
Following this, the seal ring 55a is fitted in to be fixed to the inner circumferential surface of the vehicle outer side end portion of the outer ring 53 (refer to FIG. 12), and the vehicle inner side end portion of the hub main body 51 is inserted from a vehicle outer side opening of the outer ring 53 in such a state, and the first tapered rollers 54a retained by the cage 60a are provided on the outer circumferential surface of the second inner ring raceway 58b (refer to FIG. 13). Then, although illustration is omitted, the inner ring 52 in which the second tapered rollers 54b are provided on the second inner ring raceway 58b is inserted from the vehicle inner side opening of the outer ring 53, and the inner ring 52 is fitted on to be fixed to the outer circumferential surface of the vehicle inner side end portion of the hub main body 51. Thereafter, the seal ring 55b is fitted in to be fixed to the inner circumferential surface of the vehicle inner side end portion of the outer ring 53, whereby the hub unit can be obtained.
In addition, it is described in Patent Document No. 1 that when assembling the hub unit in the way described above, a cylindrical support table is used to support the tapered rollers 54a from below in the steps shown in FIGS. 11 to 12 with a view to shorten the assembling time and to give a proper preload to the rollers.
According to the assembling method and apparatus described in JP-A-2004-257553, although the assembling time of the hub unit can be shortened more than the other conventional methods and apparatuses, when mounting the tapered rollers on the cage, the worker needs to place a plurality of tapered rollers in pockets of the cage one by one, and this increases the production costs and imposes a limitation on to the efforts to shorten the assembling time.